The printer itself only costs $8,000. The files are stored on servers outside the US.

. . . Defense Distributed does not host the files in the US; instead it has uploaded them to the Mega website run by the internet entrepreneur Kim Dotcom, based in New Zealand, and where user information – including who has logged into the site and downloaded files – is encrypted.The files have also been uploaded to the Pirate Bay file-sharing site, where they have proved a popular download.The gun blueprints take the form of computer-aided design files, which have to be read by specialist software which can then be used by industrial 3D printers to build up the hair-thin layers, one by one, to create the finished parts.On Thursday, a British expert in 3D printing and a ballistics expert separately warned that building a gun from the parts could be lethal to the user, because the physics involved in firing a bullet – with pressures in the gun chamber of more than 1,000 atmospheres, and temperatures of over 200C – could put catastrophic stresses on the plastics used it its construction.Even so, two British newspapers are understood to have asked 3D printing companies to try to build the gun for them. . . .